.NET/Java PDF, Tiff, Barcode SDK Library

Listing 9-11 shows a prototypical use of quotations, in this case to perform error estimation on F# arithmetic expressions. Listing 9-11. Error Analysis on F# Expressions Implemented with F# Quotations open Microsoft.FSharp.Quotations open Microsoft.FSharp.Quotations.Typed open Microsoft.FSharp.Quotations.Raw type Error = Err of float let rec errorEstimateAux t (env : Map<_,_>) = match t with | GenericTopDefnApp <@@ (+) @@> (tyargs,[xt;yt]) -> let x,Err(xerr) = errorEstimateAux xt env let y,Err(yerr) = errorEstimateAux yt env (x+y,Err(xerr+yerr)) | GenericTopDefnApp <@@ (-) @@> (tyargs,[xt;yt]) -> let x,Err(xerr) = errorEstimateAux xt env let y,Err(yerr) = errorEstimateAux yt env (x-y,Err(xerr+yerr)) | GenericTopDefnApp <@@ ( * ) @@> (tyargs,[xt;yt]) -> let x,Err(xerr) = errorEstimateAux xt env let y,Err(yerr) = errorEstimateAux yt env (x*y,Err(xerr*abs(x)+yerr*abs(y)+xerr*yerr)) | GenericTopDefnApp <@@ ( / ) @@> (tyargs,[xt;yt]) -> let x,Err(xerr) = errorEstimateAux xt env let y,Err(yerr) = errorEstimateAux yt env (x/y,Err(xerr*abs(x)+abs(1.0/y)/yerr+xerr/yerr)) | GenericTopDefnApp <@@ abs @@> (tyargs,[xt]) -> let x,Err(xerr) = errorEstimateAux xt env (abs(x),Err(xerr)) | Let((var,vet), bodyt) -> let varv,verr = errorEstimateAux vet env errorEstimateAux bodyt (env.Add(var.Name,(varv,verr))) | App(ResolvedTopDefnUse(info,Lambda(v,body)),arg) -> errorEstimateAux (MkLet((v,arg),body)) env

ssrs code 128 barcode font, ssrs code 39, ssrs data matrix, winforms pdf 417 reader, winforms qr code reader, winforms upc-a reader, c# remove text from pdf, replace text in pdf using itextsharp in c#, winforms ean 13 reader, c# remove text from pdf,

In the event that the preceding UPDATE statement was to be performed against a subset of the rows (it had a WHERE clause, and other users were modifying the columns this UPDATE was using in the WHERE clause), then there would be a case either for using a series of smaller transactions rather than one large transaction or for locking the table prior to performing the mass update The goal here would be to reduce the opportunity for restarts to occur If we were to UPDATE the vast majority of the rows in the table, that would lead us toward using the LOCK TABLE command In my experience, however, these sorts of large mass updates or mass deletes (the only statement types really that would be subject to the restart) are done in isolation.

That large, onetime bulk update or the purge of old data generally is not done during a period of high activity Indeed, the purge of data should not be affected by this at all, since you would typically use some date field to locate the information to purge, and other applications would not modify this data..

| Var(x) -> env.[x] | Double(n) -> (n,Err(0.0)) | _ -> failwithf "unrecognized term: %A" t let rec errorEstimateRaw (t : Expr) = match t with | Lambda(x,t) -> (fun xv -> errorEstimateAux t (Map.of_seq [(x.Name,xv)])) | ResolvedTopDefnUse(info,body) -> errorEstimateRaw body | _ -> failwithf "unrecognized term: %A - expected a lambda" t let errorEstimate (t : Expr<float -> float>) = errorEstimateRaw t.Raw The inferred types of the functions are as follows: val errorEstimateAux : Expr -> Map<ExprVarName,(float * Error)> -> float * Error val errorEstimateRaw : Expr -> (float * Error -> float * Error) val errorEstimate : Expr<(float -> float)> -> (float * Error -> float * Error) That is, errorEstimate is a function that takes an expression for a float -> float function and returns a function value of type float * Error -> float * Error. Let s see it in action, though. First we define the prefix function ( ) and a pretty-printer for float * Error pairs, here using the Unicode symbol for error bounds on a value: > let ( ) x = Err(x);; val : float -> Error > fsi.AddPrinter (fun (x:float,Err(v)) -> sprintf "%g %g" x v);; val it : unit = () > errorEstimate <@ fun x -> x+2.0*x+3.0*x*x @> (1.0, 0.1);; val it : float * Error = 6 0.61 > errorEstimate <@ fun x -> let y = x + x in y*y + 2.0 @> (1.0, 0.1);; val it : float * Error = 6 0.84 The key aspects of the implementation of errorEstimate are as follows:

Let s now look at the second reason developers are tempted to commit updates in a procedural loop, which arises from their (misguided) attempts to use a limited resource (undo segments) sparingly This is a configuration issue; you need to ensure that you have enough undo space to size your transactions correctly Committing in a loop, apart from generally being slower, is also the most common cause of the dreaded ORA-01555 error Let s look at this in more detail As you will appreciate after reading s 1 Developing Successful Oracle Applications and 7 Concurrency and Multi-versioning, Oracle s multi-versioning model uses undo segment data to reconstruct blocks as they appeared at the beginning of your statement or transaction (depending on the isolation mode) If the necessary undo information no longer exists, you will receive an ORA-01555: snapshot too old error message and your query will not complete.